Disentangling surface and bulk transport in topological-insulator $p$-$n$ junctions

Abstract

By combining $n$-type $\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3$ and $p$-type $\mathrm{S}{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3$ topological insulators, vertically stacked $p$-$n$ junctions can be formed, allowing to position the Fermi level into the bulk band gap and also tune between $n$- and $p$-type surface carriers. Here we use low-temperature magnetotransport measurements to probe the surface and bulk transport modes in a range of vertical $\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3/S{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3$ heterostructures with varying relative thicknesses of the top and bottom layers. With increasing thickness of the $\mathrm{S}{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3$ layer we observe a change from $n$- to $p$-type behavior via a specific thickness where the Hall signal is immeasurable. Assuming that the the bulk and surface states contribute in parallel, we can calculate and reproduce the dependence of the Hall and longitudinal components of resistivity on the film thickness. This highlights the role played by the bulk conduction channels which, importantly, cannot be probed using surface sensitive spectroscopic techniques. Our calculations are then buttressed by a semi-classical Boltzmann transport theory which rigorously shows the vanishing of the Hall signal. Our results provide crucial experimental and theoretical insights into the relative roles of the surface and bulk in the vertical topological $p$-$n$ junctions.

arXiv comment11 pages, 5 figures

References in corpus (24)

• Topological Insulators
• Chiral tunneling and the Klein paradox in graphene
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd${}_3$As${}_2$
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Large bulk resistivity and surface quantum oscillations in the topological insulator Bi2Te2Se
• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Non-saturating magnetoresistance in heavily disordered semiconductors
• Band structure engineering in (Bi1-xSbx)2Te3 ternary topological insulators
• Bulk Band Gap and Surface State Conduction Observed in Voltage-Tuned Crystals of the Topological Insulator Bi${}_2$Se${}_3$
• Ambipolar Field Effect in Topological Insulator Nanoplates of (BixSb1-x)2Te3
• Linear magnetoresistance caused by mobility fluctuations in the n-doped Cd3As2
• Electrically tunable surface-to-bulk coherent coupling in topological insulator thin films
• Exciton condensation and charge fractionalization in a topological insulator film
• Tunable Surface Conductivity in Bi2Se3 Revealed in Diffusive Electron Transport
• Weak Localization and Antilocalization in Topological Insulator Thin Films with Coherent Bulk-Surface Coupling
• Realization of a vertical topological p-n junction in epitaxial $\mathrm{S}{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3/B{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3$ heterostructures
• The fate of topological-insulator surface states under strong disorder
• Magnetotransport and induced superconductivity in Bi based three-dimensional topological insulators
• Growth, characterization, and transport properties of ternary (Bi1-xSbx)2Te3 topological insulator layers
• Spin-based Mach-Zehnder interferometry in topological insulator p-n junctions
• Topological states and phase transitions in Sb${}_2$Te${}_3$-GeTe multilayers
• Optical Modulation Effects on Nonlinear Electron Transport in Graphene in Terahertz Frequency Range

Cited by in corpus (8)

• Observation of Planar Hall Effect in Topological Insulator -- Bi${}_2$Te${}_3$
• Interplay of Lorentz-Berry forces in position-momentum spaces for valley-dependent impurity scattering in alpha-T3 lattices
• Transport properties of band engineered p-n heterostructures of epitaxial Bi${}_2$Se${}_3$/(Bi${}_{1-x}$Sb${}_x$)${}_2$(Te${}_{1-y}$Se${}_y$)${}_3$ topological insulators
• Long-lived non-equilibrium superconductivity in a non-centrosymmetric Rashba semiconductor
• Thickness dependence of electron-electron interactions in topological p-n junctions
• Chirality relaxation in low-temperature strongly Rashba-coupled systems
• Defect capturing and charging dynamics and their effects on magneto-transport of electrons in quantum wells
• Tracing Dirac points of topological surface states by ferromagnetic resonance